Process for the treatment of copper ores and the recovery of their values.



G. S. VADNER.

PROCESS FOR THE TREATMENT OF COPPER ORBS AND THE RECOVERY OF THEIR VALUES.

APPLICATION FILED DEC. 9, 1913.

1 1 1 1 74 Patented Sept. 29, 1914.

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1 UNITED STATES PATENT OFFICE.

cnannns s. VADNER, or SALT LAKE crrmu'mrr.

PROCESS FOR THE TREATMENT OF COPPER GEES-AND THE RECOVERY OF THEIR VALUES.

Specification of Letters Patent.

Patented Sept. 29, 1914..

To all whom it may concern:

Be it knownthat 1, CHARLES S. YAnNnn, a citizen of the United States, a resident of -Salt Lake City and Salt Lake county, State of Utah, have discovered a new anduseful Process for the Treatment of Copper Ores and the Recovery of Their Values.

It is a well known fact that the recovery of copper and other values from ores by hydro metallurgical methods presents serious difficulties with the finalre'sult that the ultimate cost of the copper. and other values recovered is very high, except in one or two cases where the method of leaching with sulfuric acids and the subsequent recovery of the. copper by precipitating with iron and by electrolysis is followed.

By means of my discovery, low' grade ores that have heretofore been considered as.

carrying too little values to be successfully reduced can be treated at a small cost.

In my specifications where I refer to ores of copper I intend to include oxids, carbonates and sulfids. However the treatment of. heavy sulfids would be so slow that it would be necessary to roast them sufficiently before applying my process for the abstraction of their values.

In my process which is diagrammatically represented in the accompanying drawing, naturally oxidized or sufliciently roasted ores {which may also contain other values such as gold, silver, and iron) are crushed to the necessary fineness either dry or in a solution of sodium chlorid.

The strength of the solution depends on the amount of copper, that the ore contains. The crushing in a salt solution is necessarily applied only in the final stage of the fine crushing. This can be done in a tube mill or other similar device wherein the use of iron is excluded thereby avoiding the danger of precipitating any copper dissolved by the solvent action of the salt solution in the crushing of the ore. .By crushing the ore in a salt solution, the solvent action of the same materially reduces the time of exposure of the ores to the final solvent, thereby effecting a saving of time and expense of treatment without materially increasing the cost of crushing. Where no advantage can be derived by crushing as described in the salt solution, or where ores have to be roasted, the ores are first crushed dry and then made into a flowing pulp with a solution of sodium chlorid or any soluble chlorid. This solution can be of from 10 to 20 per cent. and is placed in any suitable tank. The liquid pulp is then showered or sprayed down a tower up which a current of sulfurous gas is caused to pass. The operationis repeated if necessary until the extraction of the copper and other values contained in the ores is completed. The pulp and. the solution fall into a sump at thebottom of the tower where it is tested and if the extraction is not satisfactory the" pulp is returned to the top of the tower, or, 1n case that more than one tower is used and the force of gravity can be utilized, it is led by gravityto the top of a second tower. In a case where the extraction is satisfactory, the

'undissolved pulp and solution isled to'a settling tank and allowed to settle. The clear solution is then decanted and permitted to drain. The bottom of the treatment tank may either be made with a filter bottom or the, pulp may be filter pressed. The

insoluble residue from which the values have been extracted as far as it is found profitable to so do, is rejected. The solution of copper ores by means of sulfurous gas and water is by no means new, but where said treatment has been attempted on a large scale without the use of salt, has been a miserable failure for the reason that the solvent action of the solution is hastened by the use of heat; the resulting solution readgly decomposes and precipitates the red cupr so I make use of heat in-my process to hasten it. The presence of an excess of salt or other soluble chlorid in the solution precludes the danger of the above red precipitate forming and should a slight precipitation form from the chillin of the solution a little live steam will rea y clear it up.

Copper ores arenot especiallyv soluble in salt solution but a salt solution impregnated with sulfur dioxid gas becomes a powerfulsolvent of copper ores and the values contained therein.

1. Leaching solution. XN8CI+XH2Q+XSO5==X(N&C18q +HzSOa 2. Dissol'ving various ores.

Green 00 er carbonate."

Ferrous carboncopper caroxid o't bonate. copper 6. Recovery of copper by electricity. cuiso +mo+elemm =zou+nssofl+o Hss01=s0i+H=o 7. Recovery of copper by iron. ou2soa+rean,o-=zcu+resosanao The advantages of using sulfur dioxid gas in connection with the salt solution are and :as follows a.

(a) Thegas in a-dry state has little or no acid reaction, but owing to the presence of Water in the salt solution, it imparts to the.

same a strong acid and quick solvent action. (b) The ease with which sulfurdioxid is driven out by heat or. a current. of compressed air from a solution of same in salt enables the useless acidity .due to the resenc" of excess of dissolved sulfur dloxid gas, to be easily and cheaply gotten rid of and. recovered for the subsequent treatment of other ores.

(c) The cheapnessof salt in general and also the sulfur dioxid gas" WlllCh can be readfly'obtained by burning common sulfur or from the roasting of ores by any suitable means. I,

(d) The fact that in smelting sulfur dioxid gas is a nuisance and its useful application to low grade ores for the extraction ofits values is certainly the practical application of scientific chemical metallurgy.

(e) The slight solubility of sulfur dioxid gas as above used amounting from one to two per cent. whereby the cost of heat or compressed air used later on to-rid the solution ofthe excess of saidgas is proportionately small.

y The clear solution decanted in the treatmenttank as above mentioned is treated as follows :1 If it is desired to separate any iron the same may contain, from the copper the solution is treated while hot, .with finely pulverized calcium carbonate whereby the iron is eventually precipitated as (Fe O ferric oxid. By not completely neutralizing the solution with calcium carbonate, the amount of iron precipitated can vbe regulated to suit the purpose of the application of the process. Before precipitating the calcium carbonate, the excess of sulfur dioxid can be gotten rid of either by heat or can be readily obtained. In case it is found desirable to previously oxidize the iron it can lie-readily. done by compressed air or a small currentof chlorin gas. The oxid of 1 iron thus obtaiuedcan be used as flux for the smelters or for the production of me- ']05 heat the coniplete precipitation of the iron tallic iron The resulting solution is allowed to cool and upon addition of more pulverized calcium carbonate together with the use of a current of compressed air blown through the solution, the copper in the said solution is readil down as a green asic carbonate which can be readily separated by any suitable means fromtheremaining solution. Any silver containedin the solution is precipitated at the same time. If it is desired to recover the copper from the above green precipitate b smelting then this precipitate is ivashe .with water and live steam, whereby and completely thrown theisaid green precipitate iswreduced to the black oxld of copper-CuO--which is of it the precipitation of the copper is allowed'to i The now cool S0111: tion can be again used in connection with sulfur dioxid gas as a solvent for more ore.

settle out of the solution,

If it is desired the iron and the copper can be precipitated as above described. and recovered together; In either case thesilver and the gold contained in the ore will be precipitated with the copper and recovered.

If it is desired for any reason to precipitate the copper before the iron, same canbe accomplished by allowing thesolution to cool and precipitating the copper as above described whereby little or none of the iron will be precipitated. I also provide in my process for the recovery" of the copper by the use of iron or electricity where cheap iron orcheap electrical power-can be had. Where it is not desirable'to smelt the copper precipitated as above described, the same is made into a pulp with water and exposed as before mentioned to sulfur dioxid gas; the resulting solution is freed of the excess of sulfur dioxid asbefore mentioned and the copper can be recovered where cheap iron is available by ridding the original solution of sulfur dioxid by air or heat and assing the solution over iron in any suitab e manner. By this treatment the iron displaces the copper yielding ferrous chlorid and metallic copper which is recovered and cast into pigs.

The ferrou's chlorid can be used in connection with sulfur dioxid for the further solu tion of copper ores. The absence of free ,acids and ferric salts would minimize the amount of iron consumed to the very lowest point and at the same time regenerate a solvent ferrous chlorid which when used by itself would hardly be considered efiicient as a solvent of copper ores, but which when so saturated with sulfur dioxid is very eflicient. The recovery. of the copper by electricity where electricity.is cheap is accomplished as follows: The copper precipitate is dissolved in a solution of sulfur dioxid in any i suitable manner and the co per is recovered by electrolyzing the said so ution in any ordinary way at a low voltage. By this means little or no oxidization of the sulfur dioxid a as occurs, a greater part of it being driven off in a free condition especially if the solution is heated. What is driven ofi" can be used for the subsequent solution of more. ore. If the slight oxidation that does take place is confined to the calcium. sulfite, contained in the solution being oxidized tosel- Tcium sulfate, .it being quite insoluble, it is precipitated and sinks to the bottom of the electrolyzing tank.

Having thus described my process what I5 claim as new and desire tosecure' by Letters Patent-is as'follows:

1. The recess which consists in dissolvingnatura ly oxidized and sufliciently roaste'dsulfidores of. copper in a solution-of sodium chlorid saturated with sulfur dioxid gas .in the presence of heat, blowing out the excess of sulfur dioxid gas and precipitating the copper as a basic copper carbonate, by adding finely pulverized calcium carbonate, to the cold solution and passing air throughthe same.

2. The process which consists in dissolving naturally oxidized and sufficiently roasted sulfid ores of copper in a solution of sodium chlorid saturated with sulfur dioxid in the presence of heat, and separating the 'undissolved portions and getting rid of any excess of sulfur dioxid by passing a current of compressed air through the solution, and treating said solution while hot with finely pulverized calcium carbonate whereby the ferrichydrate formed reacts with the arsenic and eliminates same from the solution as ferricarsenite.

3. The process which consists in dissolving oxidized and sufficiently roasted sulfid ores of. copper .in a solution of sodium chlorid saturated with sulfur dioxid gas in the presence of heat, separating the undissolved portions of ore and getting rid of any excess of sulfur dioxid by passing a current of compressed air through the solution and treating the solution while hot with finely pulverized calcium carbonate, thereby precipitatingthe iron as ferric oxid; allowing the solution to cool, precipitating the copper and silver contained therein by the addition of additional finely pulverized calcium car bonate, passing a current of compressed air through the-solution, thereby precipitating the'copper as green basic car onate together with the silver, then separating the precipitate by filtration. 3 =1 '4. The process which consists in dissolving naturally oxidized and sufficiently roasted sulfid ores of copper-in a solution of sodium chlorid saturated with sulfur dioxid gas in the presence of heat, separating the undissolved portions of ore by dacantation and filtration, getting rid of any excess of sulfur dioxid by passing a current of compressed air through the solution, treating the solution while hot with finely pulverized calcium carbonate and thereby precipitating the iron as ferric oxid; then allowing the solution to, cool and precipitating the copper and silver contained therein by addition of additional finely pulverized calcium car- 1,1 new:

In Witness whereof I have hereurito set my hand in the presence of two SllbSCllblflg' wit- 1o nesses.

CHARLES S. VADNER.

I Witnesses:

EVVA Oseoim, SAMUEL CAnmsLE. 

